During the manufacture of thin film transistor-liquid crystal display (TFT-LCD), it is necessary to accommodate a liquid crystal panel or substrate within a cassette.
When accommodating the liquid crystal panels or substrates in different dimensions, it is required to correspondingly modify a dimension of the cassette. Currently, the modification is made manually rather than by a dedicated detection device. After the modification of the dimension has been completed, the cassette may be confirmed by an operator and then used. However, the dimension of the cassette may be modified frequently each day, and there is no dedicated detection device for detecting the modified dimension of the cassette, so an error may easily occur. When the liquid crystal panels or substrates are picked from or placed into the cassette by a mechanical arm, collision may occur. As a result, the liquid crystal panels or substrates, or the mechanical arm, may be damaged, and a loss may be caused.